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BIOLOGY OF MIND
PREFACE
Until recently the study of mind, consciousness, and feelings has been a subject
for philosophy and religion, outside the province of hard science. This has changed
in just the past few years, as advances in anthropology, animal behavior, evolutionary
theory, linguistics, molecular neurobiology, psychology, and cognitive neuroscience
have brought us to the threshold of resolving questions that have occupied philosophers
for millennia:
" How does the human brain generate a "self"?
" What is the nature of the narrative "I" that we experience in our heads?
" What is the relationship between reason and emotion?
" How do genetic and environmental factors interact to determine the structure
of our brains?
Interdisciplinary approaches to these questions are making it possible to construct
models of mind and emotion that are amenable to experimental tests. The message
of this book is that each of us is a society of minds that emerge from our evolutionary
history and from the way our brains form as we grow up in a particular natural
ecology and cultural setting. Each chapter contributes a few perspectives on
the society of mind that forms, describing a subset of its elements. From our
evolutionary history we derive the genetic instructions with which we begin life,
and the particular mind and brain that each of us then grows are shaped and patterned
by our surroundings. There are many roads to understanding our minds, many different
windows through which we must peer. We approach the target from different directions
when we take up the perspectives provided by neurobiology, cognitive psychology,
animal behavior, linguistics, and evolutionary biology. We need to consider successive
glimpses of different aspects of "mind." There are many ways to model
ourselves, multiple versions of "this is I." We can utilize information
on how our nervous systems evolved over millions of years, as well as high-technology
gadgets designed to peer inside our brains as they work. This book tries to mix
these two approaches---to assemble a description of our minds as a vast collective
of agents that interact to construct an unconscious background out of which a
narrative "I" emerges. You may well discover that the new ideas we
suggest change your everyday perceptions and actions.
This writing began for the purpose of supporting a course for both science and
non-science majors at the University of Wisconsin in Madison. It has proved useful
in offering a continuous background, overview, and storyline that supports presentation
of current work in each of the areas covered. Each chapter provides the core
material for 1 to 3 of the approximately 45 lectures in a standard semester.
This present book is an effort to share with a wider audience some of the fascination
and excitement that have permeated both public and university lectures on the
subjects it addresses. It falls somewhere in between a traditional academic text
and a popular account. You will have an easier time with the book if you have
had an introductory high school or college biology course. Sidebars are used
at intervals to emphasize main points or self-exercises. At the end of each chapter
is a summary, followed by thought questions and suggestions for further reading.
Key words are italicized and defined in a glossary at the end of the book. If
you would like more information on a particular subject that interests you, the
references provided for each chapter should enable you to pursue the matter further.
Detailed citations that support many of the factual statements made in the text
can be found in complete version of this book found at https://www.dericbownds.net/bom99/Preface.html
In parts of this book, topics have been grouped in a way that corresponds to
our subjective living experience, things we do every day---hence the chapters
on perceiving mind, acting mind, emotional mind, and linguistic mind. The ideas
can become more real and interesting if we use our subjective experience to engage
them, and occasionally simple exercises are suggested to illustrate some of the
mechanisms we consider. Such exercises can be instructive and fun if we don't
lose sight of two points. First, what we think and feel is just the tip of the
iceberg, compared with what is really going on in our brains. What we are aware
of is something like the display on a computer screen as distinguished from the
inner working of the computer. Second, our subjective experience can be very
biased and distorted by factors of which we are unaware. Numerous psychological
experiments have documented that our perceptions are not necessarily naive, reporting
actual events outside or inside our bodies. Rather, they can be influenced by
what we or someone else expects us to perceive. This is why traditional scientific
inquiry insists on eventually putting our subjective insights into a form that
can be tested impersonally by independent observers. Each of us can imagine that
a particular process is going on inside our head, but it will remain thoroughly
hidden there until its presence can be inferred from a third-person experimental
demonstration.
This book encourages you to weave, through its ideas about how our minds work,
a fabric of your own personal experience, feeling the richness deepen as these
ideas inform your introspection about the mechanisms of your thinking, feeling,
and acting. Our brains can rearrange space, time, thoughts, and emotions. Some
of these processes can be made accessible to our awareness through simple mental
exercises. It is not too difficult to sense motor programs of which we are usually
unaware, to separate thoughts from emotions, and to note some of the ways in
which we generate selves. Being aware of the mind's activities in the fractions
of a second after new situations arise can have the practical consequence of
offering some new options for our behavior. Questioning our common-sense perceptions
of reality can also create a feeling of strangeness. Brain mechanisms are not
guaranteed to feel familiar, warm, and cuddly. The objective reality we assume
to be outside ourselves depends on our particular processes of perceiving it.
We begin with some background information in Chapter 1, Thinking About Thinking,
which defines some terms and considers how a biological explanation of mind and
consciousness might be approached. It is a necessary background for the four
main parts of the book. Part I, Evolving Mind, is a description of our evolutionary
history, starting with the Big Bang that created the universe and culminated
in minds that can write and read a page like this one. Chapter 2, Origins of
Mind, is an overview of the path from the appearance of the first simple behaviors
of bacteria to the complex routines of our own brains, discussing the possible
origins of such phenomena as sensations, perceptions, and emotions. It also offers
a simple description of some of the basic processes that underlie organic evolution.
Chapter 3, Structures of Mind, describes how our modern human minds encapsulate
a series of more primitive minds and brains that arose during vertebrate evolution.
It provides an introduction to brain structures and some modern techniques used
to study the brain. Chapter 4, Primate Mind, begins with a brief general discussion
of the minds of animals and then focuses on the primate line from which we are
derived, examining similarities and differences between our minds and those of
monkeys and apes. Chapter 5, Hominid Mind, discusses stages in the evolution
of intelligence in early hominids, the origins of language, and the emergence
of modern humans. We consider some of the arguments that there is a universal
evolved human psychology: that in many of our reproductive and social behaviors,
we appear to express unconscious psychological mechanisms that evolved to meet
conditions of a vanished time hundreds of thousands of years ago, long before
the invention of agriculture and cities, when humans existed as bands of hunter-gatherers.
Part II, Developing Mind, describes how the templates set by our evolutionary
history engage an ongoing interaction with the actual physical and cultural environment
we face to generate the structures and modules of our modern minds and selves.
Chapter 6, Plastic Mind, gives a brief outline of the development of our brains
and discusses the plasticity in this process that evolved to permit us to adapt
to novel or unpredictable environments. This plasticity is maintained to some
extent in our adult brains, and it underlies both the learning of new skills
and facts and the ability to recover from brain injuries. Our brains can actually
rewire themselves when we learn new manual skills or learn to discriminate some
sensory input in a more detailed way. Far from being locked in, as was thought
until only a few years ago, many nerve connections in our brains are constantly
shuffling about, testing what works best. Chapter 7, Minds and Selves, discusses
the development and construction of our human selves. This process requires elaborate
feats of learning and memory and draws on mechanisms that are a continuation
of those that were active during the early development of the brain. We look
at stages in human development and then consider interesting clues to the nature
of a self that are obtained from studies on genetics, abnormal development, and
patients with brain lesions. Nothing escapes the nudging of our genes. They set
the limits on our repertoires of development and behavior. This is not to say
we are their prisoners, but rather that we should appreciate how our options
have been shaped by them.
Part III of the book, ""Society of Mind, takes a plunge into thinking
about the many mind, brain, and body modules that underlie our perceptions and
actions in the world---modules that form as a consequence of our evolutionary
and individual developmental histories. Chapter 8, Perceiving Mind, offers a
brief description of how our brains automatically filter and select, through
processes of which we are largely unconscious, what fraction of the mass of incoming
sensory information impinging on us is relevant for awareness. We frequently
see in the external world what our previous experience leads us to expect to
see, not what is really there. This is contrary to our common-sense notion that
we see a world out there as it is, objectively. After a brief review of some
characteristics of our sensing and perceiving, we shift our focus to visual competence.
Studies on the visual brains of cats, monkeys, and humans have yielded fascinating
insights into what visual consciousness is and where it resides. Chapter 9, Acting
Mind, emphasizes the perspective that the most fundamental role of a biological
mind is to move a biological body, and to do so quickly if danger is nearby.
Mind and brain need to be defined in a way that considers the whole body and
its ongoing reciprocal interactions with its world. This chapter offers a brief
description of some of the brain structures involved in movement control and
also considers models for movement control.
In Chapter 10 of Part III, Emotional Mind, we continue a discussion, begun in
Chapter 2, of emotions as evolutionary adaptations, and then we review modern
experiments that suggest that our emotional minds are the foundation of our rational
minds. The cathedrals of our intellect are infused by the inborn emotional wiring
of our reptilian brainstem. It is much better to be informed of the ways in which
our reason can be distorted as well as enhanced by our emotions than to imagine
that we can always face the problems of the world in an objective way. Brain
pathways that process emotional responses are more rapid than those that underlie
reasoned ones, and some simple exercises will permit you to experience this distinction
for yourself. The chapter ends with a topic of contemporary significance for
most of us: how emotions that evolved as adaptations to our ancestral conditions
can easily be misapplied to our modern circumstances, leading to debilitating
stress and disease. Chapter 11, Linguistic Mind, continues discussions begun
in Chapter 5, on the evolutionary origins of language, and in Chapter 7, on the
development of language, to review evidence that underlying brain mechanisms
support the language competence that we have evolved. This leads to the formation
of localized modules in the brain that specialize in different aspects of language
comprehension and generation. The location of some of these modules is revealed
by brain lesions and also by imaging the activity of the brain during language
performance.
Part IV of the book, Modern Mind, draws together a number of threads that run
through the book to summarize our current understanding of the selves generated
by our brains---selves generated just as automatically as a bird builds a nest
or a beaver builds a dam. Chapter 12,Conscious Mind, looks from several different
angles at the consciousness we construct. Ingenious experiments of cognitive
psychology reveal agents of our minds that reorder time and space, and suggest
that our perceptions and actions can be modeled as the result of an ongoing competition
between alternative outcomes. This chapter makes the point that there is no central
place in the brain where "it all comes together" and mentions some
classical debates on whether the problem of consciousness can be solved. There
isn't any "I" inside our heads, at least in the way we commonly suppose.
Societies of neuronal agents carry out chores in a way that is more analogous
to the performance of a chamber music group than to an orchestra with a central
conductor. Further insight into the nature of our consciousness comes from studies
on its altered states, as during sleep. We are left with the clear message that
our conscious awareness is a very, very small fraction of what is going on in
our brains---that most of the activity in our heads is being carried out by another "creature" largely
inaccessible to our introspection, as alien to us as occupation by an extraterrestrial
interloper.
Chapter 13, Theoretic Mind, brings the evolutionary story to the present by first
considering the emergence of the human mind that is the basis of the explosion
of human activity and culture in the past 4000 years. This is the mind that has
generated external forms of symbol storage, such paraphernalia of our modern
lives as the books and electronic media that account for much of what is in our
heads. We all have modern minds coexisting with emotional and psychological machinery
that evolved to meet the conditions of the Paleolithic era, and such machinery
frequently is poorly suited to the conditions of modern industrial societies.
The modern rational and individualistic self that many of us take for granted
is a relatively recent phenomenon. Over most of human history, a more collective
identity prevailed. But now, more than ever before, we are not just an unconscious
part of organic evolution, but consciously and actively direct it. Does our knowledge
of the mind and the past give us a crystal ball for predicting the future evolution
of mind? The answer is no, but what we have learned does suggest some appropriate
mental tools and attitudes for approaching an understanding of the evolution
of evolution, or how change changes itself.
There is, in our efforts to understand how our human minds work, an urgency that
derives from more than just our natural curiosity, for on its present course
the human mind may be driving itself to extinction. In the last 50 years, the
human population has increased more rapidly, and we have learned more about biology,
than in all of previous human history. The rate of extinction inflicted on animal
and plant species by humans is so great that our grandchildren may know only
half the plant and animal species we see today. It is as though we all shared
a secret, unspoken plan to go on consuming the world until there is no more left.
If more people took to heart the material we will be considering---which illustrates
the relativity of our mental processes and cultural styles, how intimately we
are bound to our environment, and how many of our behaviors are adaptations to
a long vanished past---perhaps we might be less intrusive on each other and on
the environment. If we hope to shape our future in an intelligent way, we must
understand both the evolutionary past that shaped our current behavioral repertoire
and the details of how that repertoire is played out in the present.
Acknowledgments
I would like to acknowledge the early encouragement given to this book project by Owen Flanagan, Daniel Dennett, and Stephen Kosslyn. Marlin, Helen, Jonathan, and Sarah Bownds, and my partner Len Walker, have provided crucial family support. Several reviewers have provided invaluable comments, and I am indebted in particular to my colleague A.O.W Stretton for his close and critical reading of the manuscript. Several students, Cosma Shalizi, Deana Sasaki and Jean Hetzel, have provided crucial assistance with editing, and glossary and manuscript preparation. Finally, I have thoroughly enjoyed interactions with publisher Patrick Fitzgerald, developmental editor Amy Marks, and production editor Susan Graham..
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